A new threshold voltage model for deep-submicron MOSFET's with nonuniform substrate dopings

A simple but accurate threshold voltage model for deep-submicron MOSFET's with nonuniform dopings is described in this paper. A simplified quasi-delta substrate doping profile is used to approximate the nonuniformity. We apply a hyperbola function to avoid the discontinuous problem at the boundary between different doping regions. By adjusting the parameter /spl delta/, the actual gradual doping profile can be obtained. The model developed is in good agreement with two-dimensional numerical simulation.